Axillary lymph nodes are located in the armpit. This small rounded organ has the specific role of transporting the lymph, a fluid involved in defending the body, from the lymphatic vessels draining the arm into the circulatory system. Very small, axillary lymph nodes are not usually felt on palpation under the armpits, but they can sometimes appear swollen especially in cases of inflammation of part of the arm caused by a virus or bacteria. The axillary lymph nodes may also be increased in size in women with breast cancer. Various tests, such as a blood test at the initial stage, are used to find the cause of this swelling.